Fern Constituents: Triterpenoids from Adiantum capillus-veneris.

Abstract

In preceding papers of this series, 1,2) we reported the isolation of twenty-two triterpenoids, including nine new compounds from the fresh fronds of Adiantum capillus-veneris L. (Adiantaceae) collected in Japan. Further investigation of A. capillus-veneris L. collected in China and Egypt has resulted in the isolation of two new triterpenoids; viz. 4a-hydroxyfilican-3-one (1) and fern-9(11)-en-12b-ol (2) of Chinese origin, and two oleanane triterpenoids; olean-12-en-3-one (3) and olean-18-en-3-one (4) of Egyptian origin (Chart 1). In fact, 3 and 4 are the first examples of oleanane compounds from Adiantum ferns. This paper deals with the isolation and structure elucidation of these new compounds.The constituents of the crude hexane extract of these fronds were purified by various chromatographic techniques (see Experimental) to give nineteen triterpenoids, seventeen of which were known: olean-18-en-3-one (3),3) olean-12-en-3-one (4), 3) ferrn-9(11)-ene (5), 4) ferna-7,9(11)-diene (6), 4) fern-7-ene (7), 4) hop-22(29)-ene (8), 4) filic-3-ene (9), 4) neohop-12-ene (10), 4) adiantoxide (11), 1) adiantone (12), 5) fern-9(11)-en-12-one (13), 5) 28-hydroxyfern-9(11)-ene (14), 1) isoadiantone (15), 6) isoglaucanone (16), 5) hydoxyhopane (17), 5) isoadiantol (18) 5) and hydroxyadiantone (19). 5)Compound 1 was obtained as colorless needles, and its high resolution HR-MS showed M ϩ at m/z 442.3804 suggesting the molecular formula to be C 30 H 50 O 2 (Calcd, 442.3810). Its IR spectrum indicated the presence of a hydroxyl and a carbonyl group. The 1 H-NMR spectrum of 1 displayed signals for six tertiary and two secondary methyl groups, and the chemical shifts of methyl protons (H-25-H-30) resembled those of filican-3-one (20) ( Table 1). The 13 C chemical shifts of 1 were also very close to those of 20 (Table 2), except for those of C-2, C-4, C-5, C-6 and C-24. The large down field shifts of C-4 by 22.8 ppm suggested that the hydroxyl group of 1 was located at C-4.The heteronuclear multiple bond correlation (HMBC) spectrum of 1 also fully corroborated the above observation (Fig. 1) (25), and 191 (c) (27) (Chart 2) which also supported the assigned structure. The orientation of the hydroxyl group was deduced from the nuclear Overhauser enhancement spectroscopy (NOESY) spectrum of 1, which exhibited NOE correlations between the H 3 -23 and b-oriented H 3 -24, H 3 -24 and b-oriented H 3 -25, H 3 -25 and H 3 -26, and H 3 -27 and a-oriented H 3 -28 (Fig. 2), and therefore the OH group at C-4 must be a-oriented. Thus, the structure of 1 was established as 4a-hydroxyfilican-3-one.Compound 2 was obtained as a colorless needles, and its IR spectrum suggested the presence of hydroxyl group in the molecule. Its molecular formula was deduced to be C 30 (44) and 134 (e) (79) (Chart 2) in its MS indicated that 2 is a fernene derivative with a hydroxyl group at ring A, B or C of the molecule. The 1 H-NMR spectrum of 2 indicated the presence of six tertiary methyl groups, two secondary methyl groups, one trisubstituted vinylic methine ...

Squalene cyclase and oxidosqualene cyclase from a fern

“…As ACH and ACX are the first examples of SC and OSC from ferns, however, it is still difficult to draw any conclusive answer to the intriguing question of how these enzymes evolved. A. capillus-veneris produces nortriterpene constituents, adiantone (13) and isoadiantol B (14), as major secondary metabolites [15,16]. Since they are considered to derive from 22-hydroxyhopane by oxidation (Fig.…”

“…In China, the dried whole plants have been used as an antipyretic and diuretic and in the treatment of bronchitis in traditional medicine. Our extensive phytochemical studies of the fresh fronds collected in Japan resulted in the isolation of 56 triterpene derivatives, including 13 novel compounds [15,16]. Among them, adiantone (13), isoadiantol B (14), and adiantoxide (17) are the major constituents.…”

Potencial alelopático de espécies de Pteridaceae (Pteridophyta)

“…Estudos químicos realizados com esta espécie levaram ao isolamento de triterpenos hopânicos (Mukherjee et al 2001;Brahmachari & Chatterjee 2002). De Adiantum capillus-veneris L., que vegeta na China e Egito, foram isolados dois novos triterpenos hopânicos, além de diversos outros triterpenóides (Nakane et al 2002); de Adiantum incisum Pr. foram isolados diversos triterpenos (Hayat et al 2002).…”

Antidiarrheal and antispasmodic activities of <i>Adiantum capillus-veneris</i> are predominantly mediated through ATP-dependent K+ channels activation

“…Phytochemical investigations revealed alkaloids, cardiac glycosides, steroids, reducing sugars, tannins (Ishaq et al, 2014), triterpenoids such as, 30-normethyl fernen-22-one (capillirone, 1), hopan-3 -ol (capillirol B, 2), 4--hydroxyfilican-3-one, 3-,4--dihydroxyfilicane (Haider et al, 2013), isoadiantone, isoadiantol-B, 3-methoxy-4-hydroxyfilicane and 3,4-dihydroxyfilicane, flavonoids such as, quercetin, quercetin-3-O-glucoside and quercetin-3-O-rutinoside (Ibraheim et al, 2011), oleanane compounds such as, olean-18-en-3-one and olean-12-en-3-one (Nakane et al, 2002), beta-sitosterol, stigmasterol and capesterol (Marino et al, 1989) as plant constituents.…”